The ABX3-based perovskite material is named after the calcium titanate (CaTiO3) compound first found in perovskites. The perovskite structure is characterized by a corner-sharing connection of X-octahedrons centered on the B-site cations and embedded in a tetragon with the B-site ion as the apex. The cation of A-site and B-site can be occupied by a single ion or a variety of ions. According to the types and the ionic radii of the cation of A-site and B-site, perovskite materials with different microstructures and different physical properties can be constructed.
Perovskite material is a solution processable semiconducting material with characteristics of low cost, high carrier mobility and large optical absorption coefficient. In recent years, perovskite materials have very good performance in the field of solar cells. In the meantime, perovskite materials have luminescent properties such as tunable emission wavelength and narrow emission spectrum, and also have great potential in the fields of electroluminescence and display.
At present, methods of fabricating perovskite films include sputtering, vapor deposition, screen printing, spin coating, blade coating, roller coating and ink-jet printing, among which the cost of sputtering and vapor deposition is high, the thickness and precision of screen printing are not well control light-emitting diode, spin coating is not suitable for mass production, but roller coating and ink-jet printing can be applied to low-cost, continuous, large-scale industrial production. Compared with the roller coating, ink-jet printing has the advantages of accurately control of thickness and position, micron-level resolution, capability of achieving full digital graphics output, flexibility and high precision control of process through the computer. Perovskite can be dispersed in solvent to prepare ink. By using the inkjet printing technology, the quantum dot material be can accurately deposited in the required position to form a precise pixel film, which is conducive to fabricate the perovskite light-emitting diode devices and reduce costs.
However, the existing perovskite materials generally have poor film-forming properties and pinholes formed during the film-forming process can easily lead to higher leakage current and lower current efficiency of the fabricated perovskite light-emitting diode devices.